More Cairo Shadow Work

WebKit Uber-Hacker Dirk Schulze has been hard at work on his SVG (and general graphic) filter modifications in WebKit. It now seems that drop-shadow support will be very doable using the existing Cairo backend. I am still spending a bit of time porting the work over to the Skia backend, but took a break from that to try out a few of Dirks updates, as well as attempting to correct some WebKit bugs manifested by enabling filters under Windows.

As you can see from the first image, Dirk has gotten very nice looking stroke shadows. Likewise, he has gotten proper image masked shadows working, shown in the second image. I'm quite impressed with the facility's ability to generate a correct shadow from the generated gradient. The page shows a few other examples, but these highlight the main idea.

On the Skia front, I've gotten WebCore building, and a partially functioning WebKit build. However there's still a few things I need to reconnect. It looks like there are a few things that live in "platform/graphics/chromium" that might make more sense in "platform/graphics/skia" (namely ImageBufferData.h, and perhaps some of the font and icon handling.) It also seems like the Skia backend is not as fast as the Cairo backend. This is currently a purely subjective observation, and of course neither backend is currently taking advantage of any hardware acceleration (well, actually Cairo probably is). However, the presence of the compositing and 3D transform support in Skia still make this look like a good choice, especially when attempting to address 29813.